On Wed, 29 Aug 2012, Michael Meissner wrote: > On Wed, Aug 29, 2012 at 01:56:05PM -0400, Hans-Peter Nilsson wrote: > > On Wed, 29 Aug 2012, Segher Boessenkool wrote: > > > On some systems the timebase runs at a rather low frequency, say 20MHz. > > > This test will spuriously fail there. Waste a million CPU cycles before > > > reading TB the second time? > > > > Waste said million cycles portably by calling sched_yield()? > > (Available only on POSIX systems. :) > > Well only for a test environment. You don't want to call sched_yield in the > normal case, since the apps that do this many millions of times need this to > be > as a fast as possible.
Surely, but IMHO what goes for the normal case is not a valid reading of "waste"..."millions of cycles". ;) Point being, for simulator environments, you may not want the loop that was suggested later. On the other hand, that might not be an observable period, either. brgds, H-P
